目的:探讨灌服不同剂量异补骨脂素(isopsoralen,ISO)对小鼠骨折及血管愈合的影响.方法:选取2月龄体质量为(20±2)g的雄性C57BL/6小鼠60只,采用随机数字表法分为4组:模型组(Model)、低剂量组(isopsoralen-low dose,ISO-L)、中剂量组(isopsoralen-medium dose,ISO-M)和高剂量组(isopsoralen-high dose,ISO-H),每组 15 只.建立右侧胫骨骨折模型.术后采用灌胃给药,ISO-L组、ISO-M组和ISO-H组分别灌服ISO的浓度为10、20和40 mg·kg-1,Model组灌服等体积生理盐水,每日1次,连续给药28d.每周称量体重 1次.分别于第7、14、21、28天行X线检查,并采用改良后I.R.Garrett评分对骨痂生长情况进行评价.至28 d后取材,剥离主要脏器称重并计算脏器系数,进行脏器苏木素伊红染色(hematoxylin-eosin,HE)观察病理结构变化.采用微计算机断层扫描技术(Micro-CT)扫描骨折区域并进行三维重建得出效果图,量化骨体积分数(bone volume/total volume,BV/TV).将脱钙后的胫骨进行石蜡包埋并切片,通过HE染色和番红固绿染色观察骨折断端愈合及塑形情况.通过血管灌注Microfil造影剂后取出右侧胫骨并脱钙,使用Micro-CT扫描骨折区域骨痂微血管,比较血管体积分数及血管直径.结果:给药28d后,各组小鼠体质量及器官系数比较,差异无统计学意义(P>0.05),脏器HE染色未发现明显病理学改变.X线片和改良后I.R.Garrett评分结果显示,ISO-M组28 d评分高于Model组(P<0.05);ISO-H组第14、21、28天评分均高于其他3组(P<0.05).Micro-CT结果显示,ISO-M组腔内骨痂明显减少,低于Model组(P<0.05);ISO-H组骨痂大部分消退,BV/TV均低于其他3组(P<0.05).HE染色及番红固绿染色结果显示ISO-H组骨折区域断端闭合,已出现连续板层骨,骨折愈合进程超过其他组.血管造影结果显示,ISO-H组和ISO-M组血管体积分数高于Model组和ISO-L组(P<0.05),ISO-H组和ISO-M组血管直径高于Model组和ISO-L组(P<0.05).结论:ISO在10~40 mg·kg-1浓度范围内无明显毒副作用,可以改善骨微结构,促进骨痂微血管的生成,呈浓度依赖性加速小鼠骨折断端的愈合.
Objective To explore effects of isopsoralen(ISO)with different doses on fracture and vascular healing in mice.Methods Sixty 2-month-old male C57BL/6 mices with body mass of(20±2)g were selected and divided into 4 groups by random number table method:model group(model),low dose group(isopsoralen-low dose,ISO-L),medium dose group(isopsoralen-medium dose,ISO-M)and high dose group(isopsoralen-high dose,ISO-H),with 15 animals in each group.The right tibial fracture model was established.After operation,ISO-L group,ISO-M group and ISO-H group were given ISO con-centration of 10 mg·kg-1,20 mg·kg-1 and 40 mg·kg-1,respectively.Model group was given same volume of normal saline once a day for 28 days.Weighed once a week.X-ray was performed on 7,14,21 and 28 days,respectively,and modified I.R.Garrett scoring method was used to evaluate callus growth.After 28 days,the main organs were stripped and weighed,and organ coeffi-cients were calculated.Hematoxylin eosin staining(HE staining)was performed on the organs to observe whether there were pathological structural changes.Micro-computed tomography(Micro-CT)was used to scan fracture area and conduct three-dimensional reconstruction to obtain the effect map,and quantify bone volume fraction(bone volume/total volume,BV/TV).After decalcification,the tibia was embedded in paraffin wax and sectioned.The healing and shape of fracture end were ob-served by HE staining and ferruxin solid green staining.The right tibia was removed and decalcified after intravascular infusion of Microfil contrast agent.Micro-CT was used to scan the callus microvessels in the fracture area,and the vascular volume fraction and vessel diameter were quantified.Results After 28 days of administration,there was no significant difference in body mass and organ coefficient among all groups(P>0.05),and no significant pathological changes were found in HE staining of organs.The results of X-ray and improved I.R.Garrett score showed that ISO-M group was higher than that of Model group at 28 days(P<0.05).Scores of ISO-H group at 14,21 and 28 days were higher than those of the other 3 groups(P<0.05).Mi-cro-CT results showed intracavitary callus in ISO-M group was significantly reduced,which was lower than that in Model group(P<0.05),most of the callus in ISO-H group were subsided,and BV/TV in ISO-H group was lower than that in the other 3 groups(P<0.05).The results of HE staining and ferrubens solid green staining showed fracture area of ISO-H group was closed,continuous laminar bone had appeared,and the fracture healing process was higher than that of other groups.Angio-graphic results showed vascular volume fraction in ISO-H and ISO-M groups was higher than that in Model and ISO-L groups(P<0.05),and the vascular diameter in ISO-H and ISO-M groups was higher than that in Model and ISO-L groups(P<0.05).Conclusion In the concentration range of 10-40 mg·kg-1,ISO has no obvious toxic and side effects,and could improve bone microstructure,promote formation of callus microvessels,and accelerate healing of fracture ends in a concentration-dependent manner.